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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/AvailableMemoryTracker.h"
#if defined(XP_WIN)
# include <windows.h>
# include "nsIMemoryReporter.h"
#endif
#include "nsIObserver.h"
#include "nsIObserverService.h"
#include "nsIRunnable.h"
#include "nsISupports.h"
#include "nsThreadUtils.h"
#include "nsXULAppAPI.h"
#include "mozilla/Mutex.h"
#include "mozilla/Services.h"
#if defined(MOZ_MEMORY)
# include "mozmemory.h"
#endif // MOZ_MEMORY
using namespace mozilla;
Atomic<uint32_t, MemoryOrdering::Relaxed> sNumLowPhysicalMemEvents;
namespace {
#if defined(XP_WIN)
static int64_t LowMemoryEventsPhysicalDistinguishedAmount() {
return sNumLowPhysicalMemEvents;
}
class LowEventsReporter final : public nsIMemoryReporter {
~LowEventsReporter() {}
public:
NS_DECL_ISUPPORTS
NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
nsISupports* aData, bool aAnonymize) override {
// clang-format off
MOZ_COLLECT_REPORT(
"low-memory-events/physical", KIND_OTHER, UNITS_COUNT_CUMULATIVE,
LowMemoryEventsPhysicalDistinguishedAmount(),
"Number of low-physical-memory events fired since startup. We fire such an "
"event when a windows low memory resource notification is signaled. The "
"machine will start to page if it runs out of physical memory. This may "
"cause it to run slowly, but it shouldn't cause it to crash.");
// clang-format on
return NS_OK;
}
};
NS_IMPL_ISUPPORTS(LowEventsReporter, nsIMemoryReporter)
#endif // defined(XP_WIN)
/**
* This runnable is executed in response to a memory-pressure event; we spin
* the event-loop when receiving the memory-pressure event in the hope that
* other observers will synchronously free some memory that we'll be able to
* purge here.
*/
class nsJemallocFreeDirtyPagesRunnable final : public Runnable {
~nsJemallocFreeDirtyPagesRunnable() = default;
#if defined(XP_WIN)
void OptimizeSystemHeap();
#endif
public:
NS_DECL_NSIRUNNABLE
nsJemallocFreeDirtyPagesRunnable()
: Runnable("nsJemallocFreeDirtyPagesRunnable") {}
};
NS_IMETHODIMP
nsJemallocFreeDirtyPagesRunnable::Run() {
MOZ_ASSERT(NS_IsMainThread());
#if defined(MOZ_MEMORY)
jemalloc_free_dirty_pages();
#endif
#if defined(XP_WIN)
OptimizeSystemHeap();
#endif
return NS_OK;
}
#if defined(XP_WIN)
void nsJemallocFreeDirtyPagesRunnable::OptimizeSystemHeap() {
HEAP_OPTIMIZE_RESOURCES_INFORMATION heapOptInfo = {
HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION};
::HeapSetInformation(nullptr, HeapOptimizeResources, &heapOptInfo,
sizeof(heapOptInfo));
}
#endif // defined(XP_WIN)
/**
* The memory pressure watcher is used for listening to memory-pressure events
* and reacting upon them. We use one instance per process currently only for
* cleaning up dirty unused pages held by jemalloc.
*/
class nsMemoryPressureWatcher final : public nsIObserver {
~nsMemoryPressureWatcher() = default;
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
void Init();
};
NS_IMPL_ISUPPORTS(nsMemoryPressureWatcher, nsIObserver)
/**
* Initialize and subscribe to the memory-pressure events. We subscribe to the
* observer service in this method and not in the constructor because we need
* to hold a strong reference to 'this' before calling the observer service.
*/
void nsMemoryPressureWatcher::Init() {
nsCOMPtr<nsIObserverService> os = services::GetObserverService();
if (os) {
os->AddObserver(this, "memory-pressure", /* ownsWeak */ false);
}
}
/**
* Reacts to all types of memory-pressure events, launches a runnable to
* free dirty pages held by jemalloc.
*/
NS_IMETHODIMP
nsMemoryPressureWatcher::Observe(nsISupports* aSubject, const char* aTopic,
const char16_t* aData) {
MOZ_ASSERT(!strcmp(aTopic, "memory-pressure"), "Unknown topic");
nsCOMPtr<nsIRunnable> runnable = new nsJemallocFreeDirtyPagesRunnable();
NS_DispatchToMainThread(runnable);
return NS_OK;
}
} // namespace
namespace mozilla {
namespace AvailableMemoryTracker {
void Init() {
// The watchers are held alive by the observer service.
RefPtr<nsMemoryPressureWatcher> watcher = new nsMemoryPressureWatcher();
watcher->Init();
#if defined(XP_WIN)
RegisterLowMemoryEventsPhysicalDistinguishedAmount(
LowMemoryEventsPhysicalDistinguishedAmount);
#endif // defined(XP_WIN)
}
} // namespace AvailableMemoryTracker
} // namespace mozilla
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